To reduce the cost of testing biological specimens, automated biological specimen testing systems have been developed whereby test tubes containing biological fluid are conveyed in assembly-line fashion to one or more automated testing stations. Bar codes labels are affixed to each test tube to indicate to the testing station the desired test to be performed. Each test may involve the separation of the biological fluid into multiple portions. Therefore, it is desirable for empty secondary test tubes to be available for insertion into the assembly line on demand behind each specimen.
Randomly-oriented test tubes can be purchased in bulk and stored in a test tube hopper for use as the secondary test tubes. However, randomly-oriented test tubes are not desirable for use in assembly line biologic specimen testing since the test tubes must be properly oriented by hand prior to labeling and insertion into the assembly line. For this reason, medical testing laboratories generally purchase packages of pre-oriented bulk test tubes for use as the secondary test tubes. Still, pre-oriented test tubes are expensive since the test tubes must be pre-oriented and packaged by hand before being shipped to the laboratory. Therefore, there is a need for a system which automatically extracts randomly-oriented test tubes from a test tube hopper and orients the test tubes prior to packaging or specimen testing.
Vibratory bowls are well known mechanisms capable of orienting small parts from a vessel containing randomly-oriented parts. Vibratory bowls include a small open-mouthed bowl for retaining the randomly-oriented parts, and a discharge channel provided adjacent the mouth. The vibratory bowl generally has a saw-tooth vibratory waveform which serves to urge the parts from the bowl and along the discharge channel with a consistent orientation. However, vibratory bowls are very expensive. Furthermore, as the radius of the bowl must increase according to the size of the parts to be oriented, the cost of a vibratory bowl having a size sufficient for orienting test tubes would be prohibitive. Accordingly, there remains a need for a cost-effective solution for extracting randomly-oriented test tubes from a hopper with a consistent orientation.